The present invention pertains to a method and apparatus for the treatment of wastewaters, more specifically, sanitary wastewaters, with a combination of materials, apparatus and equipment for both improvement of the treatment processes as well as the creation of additional treatment capacity. More particularly, the present invention pertains to a method and apparatus for retrofitting an activated sludge process, either anoxic or oxic with high surface area materials as well as either intermittently or continuously feeding of selected biological and zeolitic material.
Over the past 10-15 years there has been an increase in the use of the Suspended Attached Growth systems in the activated sludge processes because of the inherently more efficient batch settling and often higher treatment efficiency for contaminants removal than is possible with the conventional suspended growth activated sludge process. One modification of the activated sludge process is referred to as the SBR (Sequencing Batch Reactor) process which uses the same vessel for batch biological reactions and quiescent batch settling. Thus, the SBR process eliminates the major cost of dedicated final clarifiers necessary for the conventional flow through activated sludge process.
Wide variations in both the hydraulic and biological loading as well as temperature in either suspended or suspended/attached growth activated sludge treatment process give rise to numerous operating problems as well as process inefficiency. Sequencing Batch Reactor operations become problematic when the volume or wastewater characteristics exceed the ranges designed into the timers employed by truly batch operations. Any agent or combination of agents that can improve or expand the range of the operation band for batch type plants, as well as for flow through plants, will reduce the operating requirements as well as compliance excursions with effluent standards as well as being cost effective.
A particular plant was experiencing wide variations in applied hydraulic and organic loadings due to seasonal/recreational activities, e.g. weekend vs. weekday flows. Superimposed on top of these varying loads was a large educational complex with its related variations in flows due to varying operation schedules as well as wastewater characteristics. In addition, the educational complex generated wastewater that was high in ammonia which was transported to the wastewater treatment plant via an 18,000 foot long force main laid in bedrock which acted as a refrigeration unit for 5 months out of the year, assuring wastewater at temperatures in the 4 to 5° C. (39.2 to 41.0° F.) range. The plant, when purchased by a new owner, had to address the compliance issues inherited with the purchase of the facility.
The raw waste exhibited ammonia nitrogen levels in the range of 50 to 90+mg/l with Chemical Oxygen Demand (COD) levels as high as 1100+mg/l as well as temperatures of 4° C. Adjustment of the sequence times for longer aeration and mixing to address the reduction of these values was met with limited success. In addition, due to the wide swings in wastewater characteristics, swings in food to organism ratios were incurred with the resulting decrease in the settleablilty of the sludge and subsequent loss of solids during the decant sequence of the plant. The plant also had problems meeting its nitrate and nitrite requirements year round.
Zeolites have been successfully employed for improved wastewater treatment plant performance in accordance with the published literature and can provide a stabilizing effect during both long term and short term so fluctuations in sludge settleablilty and bacterial mass in the activated sludge process, especially SBR type of plants, are improved. It provides not only a weighting agent for increasing the sludge settling characteristics but also a platform for bacterial growth which performs a function similar to that of a suspended attached growth system.
Biological agents available from Organica Biotech Inc. have improved the performance of activated sludge processes, both aerobic and anoxic for the removal of carbonaceous as well as nitrogenous materials.
A number of devices exist for placing materials in wastewater environments as well as a number of patented materials for improvement of wastewater treatment. The materials take on many physical shapes and sizes primarily being constructed of plastic materials which provide a high surface area where biological growth can occur.
A number of patents describe methods and devices for using microbes to treat organic wastes in sewers and other similar environments. Several of these patents disclose processes which use containers that can be immersed or submerged directly into the waste-laden environments to be treated. Examples of such patents include U.S. Pat. No. 4,670,149 to Francis; U.S. Pat. No. 4,810,385 to Hater, et al.; U.S. Pat. No. 4,925,564 to Francis; U.S. Pat. No. 5,516,687 to Perez, et al., U.S. Pat. No. 5,911,877 to Perez, et al.; U.S. Pat. No. 5,879,932 to Van Erdewyk, et al.; U.S. Pat. No. 5,935,843 to Glendening, et al.; and U.S. Pat. No. 6,248,234 to Cline.